package com.longchat.utils;

public class Rc4Utils {
		public static final String KEY="wx?!@#QAZWSX123";
	    public static String decry_RC4(byte[] data, String key) {  
	        if (data == null || key == null) {  
	            return null;  
	        }  
	        return asString(RC4Base(data, key));  
	    }  
	  
	    public static String decry_RC4(String data, String key) {  
	        if (data == null || key == null) {  
	            return null;  
	        }  
	        return new String(RC4Base(HexString2Bytes(data), key));  
	    }  
	  
	    public static byte[] encry_RC4_byte(String data, String key) {  
	        if (data == null || key == null) {  
	            return null;  
	        }  
	        byte b_data[] = data.getBytes();  
	        return RC4Base(b_data, key);  
	    }  
	  
	    public static String encry_RC4_string(String data, String key) {  
	        if (data == null || key == null) {  
	            return null;  
	        }  
	        return toHexString(asString(encry_RC4_byte(data, key)));  
	    }  
	  
	    private static String asString(byte[] buf) {  
	        StringBuffer strbuf = new StringBuffer(buf.length);  
	        for (int i = 0; i < buf.length; i++) {  
	            strbuf.append((char) buf[i]);  
	        }  
	        return strbuf.toString();  
	    }  
	  
	    private static byte[] initKey(String aKey) {  
	        byte[] b_key = aKey.getBytes();  
	        byte state[] = new byte[256];  
	  
	        for (int i = 0; i < 256; i++) {  
	            state[i] = (byte) i;  
	        }  
	        int index1 = 0;  
	        int index2 = 0;  
	        if (b_key == null || b_key.length == 0) {  
	            return null;  
	        }  
	        for (int i = 0; i < 256; i++) {  
	            index2 = ((b_key[index1] & 0xff) + (state[i] & 0xff) + index2) & 0xff;  
	            byte tmp = state[i];  
	            state[i] = state[index2];  
	            state[index2] = tmp;  
	            index1 = (index1 + 1) % b_key.length;  
	        }  
	        return state;  
	    }  
	  
	    private static String toHexString(String s) {  
	        String str = "";  
	        for (int i = 0; i < s.length(); i++) {  
	            int ch = (int) s.charAt(i);  
	            String s4 = Integer.toHexString(ch & 0xFF);  
	            if (s4.length() == 1) {  
	                s4 = '0' + s4;  
	            }  
	            str = str + s4;  
	        }  
	        return str;// 0x表示十六进制  
	    }  
	  
	    private static byte[] HexString2Bytes(String src) {  
	        int size = src.length();  
	        byte[] ret = new byte[size / 2];  
	        byte[] tmp = src.getBytes();  
	        for (int i = 0; i < size / 2; i++) {  
	            ret[i] = uniteBytes(tmp[i * 2], tmp[i * 2 + 1]);  
	        }  
	        return ret;  
	    }  
	  
	    private static byte uniteBytes(byte src0, byte src1) {  
	        char _b0 = (char) Byte.decode("0x" + new String(new byte[] { src0 })).byteValue();  
	        _b0 = (char) (_b0 << 4);  
	        char _b1 = (char) Byte.decode("0x" + new String(new byte[] { src1 })).byteValue();  
	        byte ret = (byte) (_b0 ^ _b1);  
	        return ret;  
	    }  
	  
	    private static byte[] RC4Base(byte[] input, String mKkey) {  
	        int x = 0;  
	        int y = 0;  
	        byte key[] = initKey(mKkey);  
	        int xorIndex;  
	        byte[] result = new byte[input.length];  
	  
	        for (int i = 0; i < input.length; i++) {  
	            x = (x + 1) & 0xff;  
	            y = ((key[x] & 0xff) + y) & 0xff;  
	            byte tmp = key[x];  
	            key[x] = key[y];  
	            key[y] = tmp;  
	            xorIndex = ((key[x] & 0xff) + (key[y] & 0xff)) & 0xff;  
	            result[i] = (byte) (input[i] ^ key[xorIndex]);  
	        }  
	        return result;  
	    }  
	  
}
